Sensors in Google Nest devices

Last updated: 19 August 2019

Google’s connected home devices and services rely on cameras, microphones and other sensors to provide helpful features and services. These sensors can detect things like motion, sound and temperature to protect your home and loved ones, and make your lives more convenient and comfortable. And while they make our connected home devices more useful, we understand that you, your family and your friends need to trust that we'll handle your data responsibly.  

We’ve published our commitment to privacy in the home where we’ve committed to the following:

  • When our connected-home devices include cameras, microphones, or environmental or activity sensors that detect information about your home environment, we’ll list these hardware features in the device’s technical specifications – whether they’re enabled.
  • We’ll also more clearly explain what types of information these sensors send to Google, as well as examples of how we use that information, to help you understand their purpose better.

We have published this sensors guide as part of these commitments.  We will continue to periodically update this sensors guide to add new devices, features and services, reflect changes to our existing offerings, or where applicable, provide additional details and information.

The current sensors in Google’s connected home devices and services generally fall into the following categories:

  • Cameras that record video footage and still images and detect what’s happening in the home.
  • Microphones that record audio and can detect specific sounds or motion nearby.
  • Activity sensors that detect activity or changes to the physical state of the device, such as a door sensor that detects when a door opens, or an accelerometer that detects when a device is moved.
  • Environmental sensors that detect external properties of the surrounding environment – such as temperature, humidity, light or smoke – and that can help monitor the conditions inside or around your home.
  • Control sensors that enable control of a device, such as a touch-sensitive button, or a magnetic sensor to detect the position of the ring on the Nest Learning Thermostat.

Google’s connected home devices may also contain additional sensors that monitor device operation. For example, internal device sensors can detect when a device’s battery is running low, when it’s overheating or other conditions that can affect the ability of the device to operate as intended. We’ve excluded sensors that collect only such diagnostic data from this sensors guide. In addition to enabling the features and services described, the data from the sensors listed below may also be used to perform device performance and diagnostic functions. 

Types of sensors, what they measure and examples of uses

 

Type of Sensor

What it Measures

Examples of Uses*

Cameras and Microphones

Camera (lens and image sensor)

Cameras are used to capture still images and video footage for a variety of purposes, including home monitoring, video calling and more. They can also be used as a sensor to detect things like motion, activity, people or gestures. Cameras can also be used as a biometric sensor to identify a specific person.

Nest Cam, Nest Cam IQ, Nest Hello and Google Nest Hub Max

See what’s happening near the camera. Also used to detect certain types of activity, so you can get an alert when a person or motion is detected near the camera. Depending on the camera model, where you live and whether you have a Nest Aware subscription, the camera can be used to identify a face that you’ve told it to recognise and send an alert when it recognises someone you know or a stranger.

Nest Hub Max

In addition to offering the built-in Nest Cam features described above, Nest Hub Max also uses the camera to enable video calling and video messages, personalisation with Face Match and Quick Gestures for easy device control. Additional features that use the camera may be added over time.

Microphone

Microphones detect sound waves and are used for a variety of purposes in Nest devices, including to capture speech, and as a sensor to detect specific sounds or to detect motion nearby.

Nest Cam, Nest Cam IQ and Nest Hello

Hear what’s happening near the camera. Also used for the Talk and Listen feature that lets you talk to anyone near the camera. Nest Cam IQ Indoor also allows you to talk to the Google Assistant (if you have enabled that feature).

Google Home, Google Home Mini, Google Home Max, Google Nest Hub, Google Nest Hub Max

Allows you to talk to the Google Assistant, make calls and more.

Nest Guard

Allows you to talk to the Google Assistant (if you have enabled that feature).

Nest Protect

Used by the Sound Check and Safety Checkup features to make sure that the speaker and horn are working. The microphone is not used for any other purpose and is off except when checking speaker and horn functionality.

Nest Hub

Emits ultrasonic pulses from the speaker to perform microphone diagnostics.

Nest Hub Max

Makes controlling the device when you’re nearby even easier by sensing motion near the device and showing you device controls on the screen when you approach it. Also emits ultrasonic pulses from the speaker to perform microphone diagnostics.

Activity Sensors

Accelerometer

Accelerometers measure movement of a device. They are commonly used to detect changes in orientation and adjust the device’s display layout, or to detect tampering (i.e. if a device is moved when it isn’t expected to move).

Google Home Max

Adjust lights depending on speaker orientation.

Nest Guard

Detect tampering (movement of the device when the alarm is set).

Nest Detect

Contributes to open/close detection.

Nest Connect & Nest Protect

Currently unused. Included for potential future feature enhancements.

Magnetometer

Magnetometers (also referred to as magnetic sensors) measure the strength of and changes to a magnetic field.

Nest Detect

Detect when a door or window opens or closes by sensing proximity to the included magnet.

Motion

Motion sensors detect movement of people or animals in a room.

Nest Guard & Nest Detect

Detect motion for security monitoring and occupancy for Home/Away Assist.

Occupancy

Occupancy sensors detect when someone is in a room.

Nest Learning Thermostat & Nest Thermostat E

Detect occupancy for comfort optimisation and saving energy.

Nest Protect

Detect occupancy for Home/Away Assist and to turn on Pathlight when someone walks under Nest Protect.

Proximity

Proximity sensors detect the presence of nearby objects.

Nest Learning Thermostat

Detect when someone is near the thermostat and light up the display.

Nest Guard

Detect when someone is near Nest Guard and light up the buttons on the device.

Tamper Detection Switch

Tamper detection switches are used to detect when a device is unexpectedly moved or when someone opens a case to gain access to the internals of a device.

Nest Detect

Detect when Nest Detect is removed from the backplate.

Ultrasonic

Ultrasonic sensors use sound waves to measure distance to an object and can be used to detect when someone is near a device.

Nest Protect (1st generation)

Currently inactive.

Environmental Sensors

Ambient Light Sensor

Ambient light sensors measure the amount of light in a room.

Google Home

Control display brightness.

Nest Hub & Nest Hub Max

Control display brightness and colour calibration.

Nest Learning Thermostat & Nest Thermostat E

Control display brightness and improve temperature sensor accuracy by detecting when the sun is shining on the thermostat.

Nest Cam IQ & Nest Hello

Detect day/night to switch Night Vision off and on.

Nest Protect

Detect when the room is dark so that it can automatically turn on the Pathlight and Nightly Promise features.

Nest Guard

Currently unused. Included for potential future feature enhancements.

Nest Detect

Detect when the room is dark so that it can automatically turn on the Pathlight feature.

Carbon monoxide

Carbon monoxide sensors measure the amount of carbon monoxide in the air.

Nest Protect

Detect dangerous levels of carbon monoxide in the air.

Humidity

Humidity sensors measure the amount of water (relative humidity) in the air.

Nest Learning Thermostat & Nest Thermostat E

Detect ambient humidity for comfort optimisation and control of whole-home humidifiers.

Nest Protect

Enables the Steam Check feature to reduce nuisance alarms caused by things like steam from your shower.

Nest Guard

Currently unused. Included for potential future feature enhancements.

Nest Detect

Included for potential future feature enhancements. Currently only used for monitoring device operation.

Smoke (photoelectric sensor)

Detects the presence of smoke in the air by detecting when smoke particles pass in front of an infrared light source.

Nest Protect (1st generation)

Fire/smoke detection

Smoke (Split-Spectrum sensor)

Detects the presence of smoke in the air using two wavelengths of light to look for smoke. An infrared light is used to detect larger particles generated by slow, smouldering fires, while a blue light detects smaller particles created by fast fires.

Nest Protect (2nd generation)

Fire/smoke detection

Temperature

Temperature sensors measure the current temperature. This can be the ambient temperature in a room, or the temperature inside a device.

Nest Learning Thermostat, Nest Thermostat E, Nest Heat Link E & Nest Temperature Sensor

Detect ambient room temperature for comfort optimisation.

Nest Protect

Detect sudden rises in room temperature.

Nest Guard

Currently unused. Included for potential future feature enhancements.

Nest Detect

Included for potential future feature enhancements. Currently only used for monitoring device operation.

Control Sensors

Capacitive Touch

Detects the position and motion of a person’s finger on the surface of a display or button.

Google Home, Google Home Mini, Google Home Max, Nest Hub & Nest Hub Max

Used for device control.

Magnetometer

Magnetometers (also commonly referred to as magnetic sensors) measure the strength of and changes to a magnetic field. When used for device control, a magnetometer can detect the position of an object based on changes to the magnetic field when the object is moved.

Nest Learning Thermostat (3rd generation) & Thermostat E

Detect movement of the ring for manual thermostat control.

Optical

Optical sensors measure changes to the amount of light shining on the sensor. Optical sensors can detect the position of an object by sensing whether the object is blocking a beam of light.

Nest Learning Thermostat (1st and 2nd generation)

Detect movement of the ring for manual thermostat control.

Nest ✕ Yale Lock

Detect whether the bolt is open or closed.

 

* This is a non-exhaustive list of examples of how sensors explained here are used in Google’s connected home devices and services. Our goal is to help you understand better the purpose behind these sensors, and the different ways these sensors are used in our devices and services to offer helpful features and services.  

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